This invention relates to a ratchet wrench. Simple forms of ratchet wrench may, for example, comprise a wrench head and handle with a workpiece gripping element rotatably mounted in the head and a ratchet mechanism connected between the head and the gripping element so that the ratchet mechanism provides a drive connection between the handle and the gripping element in one direction of rotation of the handle, for applying torque to a workpiece and disconnects the drive connection in the opposite direction of rotation of the handle. In this simple form of ratchet wrench, torque is applied to the gripping element directly through the handle and there is limited scope for variation of the applied torque if, for example, rapid turning of a workpiece such as a screw or nut is required when little torque is required. Accordingly, more sophisticated ratchet wrenches are known incorporating different mechanisms for varying the torque applied to the driven member so as, for example, to provide more rapid operation if little torque is required.
Examples of earlier forms of ratchet wrench are shown in the following U.S. patents:
U.S. Pat. No. 2,288,217, June 30, 1942 PA1 U.S. Pat. No. 2,530,553, Nov. 21, 1950 PA1 U.S. Pat. No. 3,286,560, Nov. 22, 1966 PA1 U.S. Pat. No. 3,447,404, June 3, 1969 PA1 U.S. Pat. No. 3,572,188, Mar. 23, 1971 PA1 U.S. Pat. No. 3,941,017, Mar. 2, 1976 PA1 U.S. Pat. No. 4,224,844, Sept. 30, 1980 PA1 U.S. Pat. No. 4,507,989, Apr. 2, 1985.